How to play ORTHO 4x4
Shuffle the 24 cards and deal 12 to each player. The player who plays first plays any card she/he chooses.
In turns, the players play a card with either the same shape or the same colour as the one played last on the pile.
When the players have no valid card to play, they pass.
If both players pass, the one who passed first can start afresh, playing any card she/he chooses.
The colors are Blue, Red, Yellow and Green, and the shapes Circle, Triangle, Rhombus and Square.
Four cards have colorless shapes and four colors without shapes.
Only a card with the same shape can be played on a card with a colorless shape.
Only a card with the same color can be played on a card with a shapeless colour.
The winner is the player who first empties his/her hand.